1. Field of the Invention
This invention relates to storage system data maintenance, and particularly to the protection of storage systems against uncorrectable media errors.
2. Description of Background
Large-scale archival storage systems lose data for a variety of reasons. As such, failures can occur at both a device level and at a storage block level. The resolution and correction of a failure must be detected early enough to be able to utilize any redundancy that may be built into a storage system. For example, within current redundant array of independent disk (RAID) systems the redundancy available across disks is utilized to reconstruct erroneous sectors or block of sectors within a data storage system. In particular, a fault-detection process known as “disk scrubbing” is implemented within RAID systems in which disk drives are periodically accessed in order to detect any storage block failures. By scrubbing all of the data stored on all of the disks, a storage block failure can be detected and compensated for by the rebuilding of any affected sectors or block of sectors. Typically, such disk scrubbing operations are performed only during idle periods because the process requires additional disk I/O requests to be issued when an erroneous sector or block of sectors is found on a disk. This aspect leads to an increase in the performance time that is required to for a scrubbing cycle to be accomplished upon a RAID.